Merge pull request #125 from drbenmorgan/support-older-g4tm

Check for G4VTrackingManager support via compilation

Author: mnovak42

CMakeLists.txt

@@ -144,6 +144,19 @@ if(G4HepEm_GEANT4_BUILD)
   endif()
 
   set(CMAKE_CXX_STANDARD ${Geant4_CXX_STANDARD}) # use value from Geant4Config.cmake
+
+  # Check if Geant4 is supports G4VTrackingManager
+  # Always available from v11.0, but experiments may backport it to earlier versions
+  # so we do a compile check.
+  include(CheckCXXSourceCompiles)
+  set(CMAKE_REQUIRED_LIBRARIES ${Geant4_LIBRARIES})
+  check_cxx_source_compiles("
+    #include \"G4VTrackingManager.hh\"
+    class testtm_ : public G4VTrackingManager {
+    public:
+      void HandOverOneTrack(G4Track*) {}
+    };
+    int main() { testtm_ model; return 0; }" G4HepEm_HAS_G4VTRACKINGMANAGER)
 else()
   # Need workaround for G4VERSION_NUM G4HepEmRun...
   # ... done in that component for now.

G4HepEm/G4HepEm/CMakeLists.txt

@@ -14,7 +14,7 @@ set(G4HEPEM_Geant4_LIBRARIES
   Geant4::G4track
 )
 
-if(Geant4_VERSION VERSION_GREATER_EQUAL 11.0)
+if(G4HepEm_HAS_G4VTRACKINGMANAGER)
   set(G4HEPEM_headers ${G4HEPEM_headers}
     include/G4EmTrackingManager.hh
     include/G4HepEmConfig.hh

apps/examples/TestEm3/CMakeLists.txt

@@ -44,7 +44,7 @@ set(sources
   src/SteppingVerbose.cc
   src/TrackingAction.cc
 )
-if(Geant4_VERSION VERSION_GREATER_EQUAL 11.0)
+if(G4HepEm_HAS_G4VTRACKINGMANAGER)
   set(sources ${sources}
     src/PhysListG4EmTracking.cc
     src/PhysListHepEmTracking.cc
@@ -55,4 +55,5 @@ endif()
 # Add the executable, and link it to the Geant4 libraries
 #
 add_executable(TestEm3 ${PROJECT_SOURCE_DIR}/TestEm3.cc ${sources})
+target_compile_definitions(TestEm3 PRIVATE $<$<BOOL:${G4HepEm_HAS_G4VTRACKINGMANAGER}>:G4HepEm_HAS_G4VTRACKINGMANAGER>)
 target_link_libraries(TestEm3 ${Geant4_LIBRARIES} ${G4HepEm_LIBRARIES})

apps/examples/TestEm3/src/PhysicsList.cc

@@ -86,8 +86,8 @@ PhysicsList::PhysicsList() : G4VModularPhysicsList(),
   fMessenger = new PhysicsListMessenger(this);
   verboseLevel = 0;
 
-#if G4VERSION_NUMBER >= 1100
-  // make the `G4HepEmTrackingManager` the default whenever it's available (g4>=11.0)
+#if G4HepEm_HAS_G4VTRACKINGMANAGER
+  // make the `G4HepEmTrackingManager` the default whenever it's available
   fEmName = G4String("HepEmTracking");
   fEmPhysicsList = new PhysListHepEmTracking(fEmName);
 #else

cmake/G4HepEmConfig.cmake.in

@@ -7,6 +7,10 @@
 # - Project properties
 set_and_check(G4HepEm_INCLUDE_DIR "@PACKAGE_G4HEPEM_EXPORTED_INCLUDE_DIR@")
 
+# Record whether we support G4VTrackingManager.
+# Note that this implies the re-found Geant4 below is the exact same as we
+# were built with, especially if G4VTrackingManager has been backported to < 11.0
+set(G4HepEm_trackingmanager_FOUND @G4HepEm_HAS_G4VTRACKINGMANAGER@)
 
 # - Project dependencies
 include(CMakeFindDependencyMacro)